1. Field of the Invention
The invention relates to an oxygen strand cutting machine for flame-cutting cast cold and hot slugs, steel blocks and slabs in and after continuous steel casting units with a crane tower and a boom arranged perpendicular to the continuous casting direction, whereon one or two torch carriages with flame cutters are mobile perpendicular to the cast strand.
2. Description of Related Art
Continuously cast steel strands in continuous casting units should be cut for further treatment in transportable lengths corresponding to the finished products. These predominantly hot slugs, blocks or slabs are separated usually by oxygen flame cutters in an oxygen strand cutting machine. In such an oxygen strand cutting machine an oxygen cutting beam transforms the steel brought to ignition temperature into an outflowing oxygen sullage and generates a seam, which grows into a cut when moving.
In most well-known embodiments of continuous flame cutting machines, these are robust portal-type machine casings made of heavy profiles and steel plates welded together, predominantly of portal type, protected with water plates against the intense heat generated from the strand, mobile on two rails arranged on both sides of the strand. A so-called slide way intended for the torch carriages by this portal carries the substantially non-protected torch carriages with the flame cutters and the hoses and cables provided, which are routed in hose and cable drag chains.
DE 10 2006 020 415.8 describes an oxygen strand cutting machine, composed substantially of a tower carriage arranged close to the part, i.e. close to the cast strand, mobile along the tower carriage with travelling mechanism, counterweight, lifting mechanism, electrical station, gas station, vertical carriages and of another tower fitted with hinges for pivoting a boom in the form of a frame, mounted rotatably, whereon one or two torch carriages inserted in cooling jackets filled with circulating water and fitted with flame cutters are mobile perpendicular to the part.
Should repair or maintenance works be necessary to the continuous flame cutting unit, operating failures of all kinds may cause the unit to shut down, which may involve enormous cost and time wasted. The staff assigned to repair and maintenance may be exposed to injuries to variable degrees due to the immediate proximity of the hot strand and of the inevitable heat radiation. To avoid such a situation and to be able to conduct maintenance work, the boom of the oxygen strand cutting machine can be retracted horizontally from the roller positioner of the cast strand, so that the arms are parallel to the continuous casting direction.
DE 10 2006 020 415.8 also shows that the tower carriage fitted with wheels and a travelling mechanism is mobile on relative long rails forming a track, anchored to corresponding foundations. Such foundations provided with rails involve a lot of technical means and are very expensive, since they have to absorb many loads and pressures.
DE 36 07 027 A1 divulges a device for flame cutting of metal scrap and waste, exhibiting a column, containing a carriage and a boom, fitted with a burner and a pivoting system for pivoting said boom. The carriage fitted with the boom hangs from the column on a flexible sheathed cable. One end of the sheathed cable is connected to a driving means of the carriage on the column, and the other end is attached to the boom using a diversion member, so that the boom is also subjected to a torque relation to its pivot axis. It also shows that the column fitted with wheels in mobile on a rail track perpendicular to the cutting direction of the torch. Still this rail track proves quite detrimental inasmuch as it involves enormous means and expenses connected to its foundations. Moreover, cutting perpendicular to the part is possible only when moving the column on the rails.